JPS58205110A - Optical fiber cable - Google Patents

Abstract

PURPOSE:To obtain an optical fiber cable having excellent temp. characteristics by forming at least one of the outermost covering of optical fiber cores and the sheath of the assemblage of the cores of a rubber material. CONSTITUTION:The coverings 2 of optical fiber cores 1 and the sheath 4 of an optical fiber cable are formed of a rubber material. A tension member 3 consists of an FRP or the like. Natural rubber having the Young's modulus which is about 1/100 of the Young's modulus of PE or nylon is used for the covering 2 and the sheath 4, whereby the coefft. of linear expansion of the cable is reduced, and as a result, the stress to be exerted on the cores 1 is kept low when temp. changes and the deterioration in the transmission characteristics is improved to make less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber cable with good temperature characteristics.

The optical fiber cable has 7 eyes as shown in Figure 1)
It has a structure in which six optical fibers with a core S and a tension member 8 are assembled at <tlal, and a cable outer plate 4 is covered with the assembled thing.

By the way, conventionally, nylon has been used as the core S at2.

Polyethylene, PVO, etc. are used, and polyethylene, PVA, etc. are used as the cable jacket 4, and all of these materials have large thermal stress. Therefore, due to temperature changes, large stress is applied to the optical fiber 1 from the core wire temporary placement 2 and the cable jacket 4.
As a result, there was a drawback that the transmission characteristics deteriorated.

Therefore, as a way to improve such temperature characteristics, if we try to increase the diameter of the tension member 3 without comparing it to the core 'sf&2E and the cable outer plate 4, we will inevitably increase the diameter of the original fiber core. It has to be made thicker, so the thickness of the cable 2 becomes thicker, and the cross-sectional area of the cable sheath 4 is also divided into layers depending on the length of the outer diameter of the cable. After all, heart 4
Temperature characteristics cannot be improved to 6th because the thermal stress of the 1i temporary recovery 2 and the 5-pull outer plate 4 is increased.

This invention was made in consideration of the above circumstances, and by forming at least one of the six outermost temporary layers of the original fiber cable and the outer sheath of the cable from a rubber material,
According to the present invention, the purpose is to provide a fiber cable with good temperature characteristics as a base, and the above-mentioned first core cover & second cable and outer cable are formed from a rubber material and the tail is formed. 1 natural rubber as a Konocom material! ! Taha synthetic rubber is used.

Next, the effectiveness of this invention will be demonstrated.

The machine tension coefficient α of the original fiber bundle is the cable l! I
The expansion coefficient, Young's modulus, and shear radius of t or material i are αi, Jji, Ai and T are given by the following formula・α
=ΣαiW+Ai/ΣgiA+ ・・・・・・
(1) Using the above formula u+'i:, and using FRP as the tension member 8, find the tensile coefficients for the original fiber cables of the three woodworkers listed below (■ to ■) and use them as shown in Fig.
■ The material of the outer panel 4 is polyethylene, and the material of the shinbai kakushi 2 is knife J# 曾 (conventional form)...shown in the song IJA.

■ When natural rubber is used as the material for the outer panel 4 and nylon is used as the material for the temporary core conductor AT2 (according to this invention).
...Indicated by white plum B.

■ When natural rubber is used for both the material of the outer cover 4 and the material of the core #jl temporary recovery 2 (according to this invention).

...Indicated by song SC.

In addition, the score coefficients used for this meter nose are calculated and shown in Table 1. As can be seen from the 1st coefficient of the Tani material, the material of the outer cover, the material of the core cover & Z as in this invention, By using a natural comb, whose Young's modulus is approximately 10° as polyethylene or nylon, the cable machine expansion coefficient can be as small as 2, and as a result, the stress applied to the optical fiber ml during temperature changes can be reduced. It is possible to significantly improve the deterioration of transmission characteristics by keeping it small. In addition, for natural rubber (/J t),
Similar effects can be obtained by using styrene-butadiene rubber, ethylene-propylene rubber, etc., which have a similar Young's modulus.

By the way, in general, in the original 7 Aipah center machine, a primary temporary layer 5 such as modified silicone resin and a loose layer 6 made of silicone resin etc.
And, it is made of secondary temporary material such as nylon or 3 layers. However, the thermal stress of the material of the secondary temporary layer 7, such as nylon, which is used to protect the original fiber from external forces, is large, and this causes large distortions in the optical fiber due to temperature changes. This caused the transmission characteristics to deteriorate.

Note that in order to protect the original fiber or to increase the core diameter of the Q-cable due to the requirements of the regulations, the secondary plate wave 7 is made thicker and the original fiber core is increased. This will significantly deteriorate the mi characteristics.

Next, the magnitude of the shadow of such a conventional secondary temporary position 7 will be clearly explained.

In the original fiber core, quartz glass is usually used as the original fiber material. This quartz glass is number one! Since the expansion coefficient is extremely small compared to the false expansion coefficient of the temporary material, when a humidity change ΔT occurs, the original fiber can be expressed by the following formula (2).
It is subjected to a thermal stress F shown by .

Here, ffG, AG, KG are the expansion coefficient of the original 7 Aipah, the cross section, the Young's modulus, αH, AL En
G; f are the linear expansion coefficient of the material to be treated, ilT surface right, and young leather, respectively.

In the above equation (2), αG, AG, and EG are parameters of the original fiber, and it is only a matter of changing them because it is necessary to strictly maintain the transmission customization. In addition, as the temporary crushing material is required to have excessive flexibility, island molecular materials are usually used, but since molecular materials are used, the αH can be reduced to a large extent by using four layers.

Therefore, in order to reduce the thermal stress F, it is necessary to reduce AH and HH. However, in the conventional case, AH and Em mostly depend on the secondary transition 7, and making AH small means thinning the thickness of f, which means that This is undesirable because it increases the impact of external forces such as crushing.

As a result, in the conventional coated optical fiber, the thermal stress of the secondary temporary holder 7 on the bare optical fiber has a large influence1, which deteriorates the temperature characteristics of the original coated fiber.

Therefore, as a practical example of this invention, nylon is used.

By applying a polyethylene layer made of a material with a high Young's modulus (see Figure 3), the thermal stress applied from the caressing material to the original fiber element during changes in humidity can be significantly reduced, thereby improving transmission during changes in temperature. Deterioration of custom-made products can be significantly suppressed.

In the summer, if it becomes necessary to increase the diameter of the original fiber core S in order to protect the original fiber from external forces such as crushing due to the design of the cable, for example, the outer layer of rubber should be made thicker. By doing so, the diameter of the original fiber core j11J can be increased without impairing the transmission characteristics during temperature changes.

In addition, if necessary, -Next Karihashi 5. Buffer layer 6゜secondary temporary a
17 can be omitted. As a result, the rubber outer layer Wc
Examples of the restoration mode of the method 8 are a form in which the original fiber material is directly coated, a form in which a primary temporary resin such as silicone resin is applied to the optical fiber material and then temporary lamination is performed, and a form in which the original fiber material is temporarily laminated. After applying a primary device 5 such as a modified silicone resin and a sharp layer 6 of silicone tree B, it is subjected to alT, and a primary device 5 such as a modified silicone resin and a silicone resin etc. are applied to the original fiber. A form M is prepared which is temporarily laminated after applying a buffer layer 6 and a secondary temporary layer 7 of nylon, polyethylene or PVA.

As explained above, according to the original fiber cable according to the present invention, since the six outermost layers of the original fiber cable and at least the knees of the outer plate of the cable are formed of a rubber material, the vortex pE Deterioration of transmission characteristics due to changes can be largely eliminated. Also,
When the outermost layer of the optical fiber core and the housing 2 are made of rubber material, it is possible to significantly suppress deterioration of transmission characteristics due to temperature changes with the same core as before, and roughly speaking, the temperature of the original fiber core can be reduced. For the purpose of embedding cable structure design or preserving optical fiber without deterioration of characteristics,
By increasing the temporary dipping thickness of the optical fiber 6, it is possible to increase the core diameter.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the original fiber cable of this title, and Figure 2 is the i! The IT diagram, Figure 3, shows the actual fit of this invention! 18
11 is a sectional view of the original fiber core wire portion, and Fig.
It is a T diagram showing a comparison of tensile coefficients. l... Original 7-eye AgH12... Cord wire insertion, 4° Pa°. Cable outer plate/8°° outer shield temporarily restored. Applicant Japan 1tli! Masatake Shiga, Agent of Yawa Public Corporation, Masatake Shiga, Figure 1, Figure 2, Figure 91”<1

Claims (1)

[Claims] In an optical fiber cable in which a number of original fiber cores that have been destroyed are assembled and a jacket is temporarily laminated on this assembly, at least one of the temporary transport of the outermost layer of the m distribution fiber core and the outer plate of the assembly. This is an optical fiber table that is covered with a rubber material.